lib/pages/settings_page.dart

@@ -1,15 +1,62 @@
 import 'package:flutter/material.dart';
+import 'package:permission_handler/permission_handler.dart';
 
 import '../l10n/app_localizations.dart';
+import '../service/notifying.dart';
+import '../service/permission_service.dart';
+import '../service/storage.dart';
 
-class SettingsPage extends StatelessWidget {
+class SettingsPage extends StatefulWidget {
   static const routeName = '/settings';
   const SettingsPage({super.key});
 
+  @override
+  State<SettingsPage> createState() => _SettingsPageState();
+}
+
+class _SettingsPageState extends State<SettingsPage> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(title: Text(AppLocalizations.of(context)!.settings)),
+      body: SizedBox(
+        width: MediaQuery.of(context).size.width * 0.9,
+        child: Column(
+          crossAxisAlignment: CrossAxisAlignment.center,
+          children: [
+            Text(
+              AppLocalizations.of(context)!.appData,
+              style: Theme.of(context).textTheme.titleLarge,
+            ),
+            ElevatedButton(
+              onPressed: () => onActivateJsonImportPressed(),
+              child: Text(AppLocalizations.of(context)!.import),
+            ),
+            ElevatedButton(
+              onPressed: () => onActivateJsonExportPressed(),
+              child: Text(AppLocalizations.of(context)!.export),
+            ),
+          ],
+        ),
+      ),
     );
   }
+
+  void onActivateJsonExportPressed() async {
+    if (await checkStoragePermission) Storage.exportToJsonFile();
+  }
+
+  void onActivateJsonImportPressed() async {
+    if (await checkStoragePermission) Storage.importFromJsonFile();
+  }
+
+  Future<bool> get checkStoragePermission async {
+    if (!(await PermissionService.requestStoragePermission).isGranted) {
+      if (mounted) {
+        Notifying.showStoragePermissionErrorSnackbar(context);
+        return false;
+      }
+    }
+    return true;
+  }
 }

lib/service/json_file_service.dart

@@ -0,0 +1,69 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:file_selector/file_selector.dart';
+import 'package:flutter/services.dart';
+
+import '../model/bookmark.dart';
+import '../model/collection.dart';
+import '../assets/constants.dart' as constants;
+
+class JsonFileService {
+  static Future<bool> exportToJson({
+    required List<Collection> collections,
+    required List<Bookmark> bookmarks,
+  }) async {
+    final dir = await _directoryPath;
+
+    final data = {
+      'collections': collections.map((c) => c.toJson()).toList(),
+      'bookmarks': bookmarks.map((b) => b.toJson()).toList(),
+    };
+    final json = jsonEncode(data).codeUnits;
+    final file = XFile.fromData(
+      Uint8List.fromList(json),
+      mimeType: 'application/json',
+      name: constants.jsonFileName,
+    );
+
+    file.saveTo('$dir/${constants.jsonFileName}');
+
+    return false;
+  }
+
+  static Future<({List<Collection> collections, List<Bookmark> bookmarks})>
+  importFromJson() async {
+    const typeGroup = XTypeGroup(label: 'json', extensions: <String>['json']);
+    final XFile? file = await openFile(
+      acceptedTypeGroups: <XTypeGroup>[typeGroup],
+    );
+
+    if (file == null) {
+      return (collections: <Collection>[], bookmarks: <Bookmark>[]);
+    }
+
+    final jsonString = await file.readAsString();
+
+    final data = jsonDecode(jsonString) as Map<String, dynamic>;
+
+    final collections = (data['collections'] as List<dynamic>? ?? [])
+        .map((json) => Collection.fromJson(json as Map<String, dynamic>))
+        .toList();
+
+    final bookmarks = (data['bookmarks'] as List<dynamic>? ?? [])
+        .map((json) => Bookmark.fromJson(json as Map<String, dynamic>))
+        .toList();
+
+    return (collections: collections, bookmarks: bookmarks);
+  }
+
+  static Future<String> get _directoryPath async {
+    if (Platform.isAndroid) {
+      return await getDirectoryPath(
+            initialDirectory: constants.defaultAndroidExportDirectory,
+          ) ??
+          '';
+    }
+    return await getDirectoryPath() ?? '';
+  }
+}

lib/service/storage.dart

@@ -4,6 +4,7 @@ import 'package:shared_preferences/shared_preferences.dart';
 
 import '../model/bookmark.dart';
 import '../model/collection.dart';
+import 'json_file_service.dart';
 
 class Storage {
   static const String _bookmarksKey = 'bookmarks';
@@ -163,4 +164,20 @@ class Storage {
     }
     return _prefsWithCache!;
   }
+
+  static Future<bool> exportToJsonFile() => JsonFileService.exportToJson(
+    collections: loadCollections(),
+    bookmarks: loadBookmarks(),
+  );
+
+  static Future<bool> importFromJsonFile() async {
+    final import = await JsonFileService.importFromJson();
+
+    if (import.bookmarks.isNotEmpty || import.collections.isNotEmpty) {
+      saveBookmarks(import.bookmarks);
+      saveCollections(import.collections);
+      return true;
+    }
+    return false;
+  }
 }